1. Technical Field of the Invention
The invention relates to a separation device for a motor vehicle with a flexible flat shaped article, which is held on a winding shaft located in a box housing between a rolled-in rest position and a pulled-out protective position which is rigidly connected to the vehicle with holding devices, in a manner so it can be rolled in and rolled out, where a return spring arrangement applies pressure in the roll-in direction onto the winding shaft.
2. The Prior Art
Such a separation device is known from WO 98/24660. The known separation device presents a flexible flat shaped article in the form of a separation net, which is held in a manner so it can be rolled in and rolled out on a winding shaft which is pivoted in a box housing. The separation net presents a dimensionally stable pull-out ledge at its front end, by means of which the separation net can be fixed, in a vertical pulled out protective position, in holding devices rigidly attached to the vehicle in the roof area of the motor vehicle. The winding shaft is associated with a relatively strong wound spring, which retracts the separation net after it has been suspended, from the holding devices rigidly attached to the vehicle, automatically in the rest position, with retraction into the box housing. In the suspended, vertical protective position, the wound spring serves the purpose of keeping the separation net tight. Because of the relatively high return forces of the wound spring, it is relatively difficult, because of the ergonomically unfavorable situation, for a person to pull the separation net out of its rest position and to suspend it in the holding devices which are rigidly attached to the vehicle. Since the box housing is accommodated in the area of storage space of the motor vehicle, an operator, to pull out the separation net, must lean at least partially into the storage space, to grab the pull-out ledge and to pull out the separation net. To obtain an ergonomically more advantageous lever, the operator must first pull the separation net approximately horizontally toward himself/herself, until the pull-out length required for the suspension has been reached. Then the pull-out ledge including the separation net is tilted upward by the operator and suspended in holding devices which are rigidly attached to the vehicle. To prevent that relatively large forces must be applied for the suspension process, during the attempted suspension, in which the separation net is held almost vertically and the operator must extend his/her arms forward to apply holding force against the return force of the wound spring, WO 98/24660 proposes a holding installation which, at least partially, eliminates the return force of the wound spring. The holding installation can be operated manually or automatically by means of a counter screw which determines the number of rotations of the winding shaft until the required pull-out length has been reached; however, it can also be switched off to achieve, after the removal from the vertical protective position, a problem-free automatic rolling up of the separation net onto the winding shaft.
In the unpublished German Patent DE 199 27 384.7, a separation device is described, which also provides for an operator friendly, at least largely low-strength, suspension of the pull-out ledge of the separation device in the vertical protective position in corresponding holding devices which are rigidly attached to the vehicle. In this patent application, the reduction of the return force is generated by a spring arrangement formed by two spring elements, where the first spring element is designed as a wound spring provided with a high return force and a second spring element is provided with a convenience spring having a weaker spring force. In this solution, the two springs are either connected in series or parallel. If the two springs are connected in series, both springs act in the same direction. Starting with a defined pull-out length, the stronger wound spring is rendered inoperative, and at the same time the weaker convenience spring is made functional. As a result, it becomes possible to suspend the pull-out ledge of the separation net with reduced force, because it is only the convenience spring which applies a corresponding return force. If the separation net is again removed from the suspension and pulled in, the convenience spring at first still acts. Then, by a corresponding mechanical switch device, an automatic switch over is carried out to the stronger wound spring, so that the latter carries out the remaining pull-in and roll-in process. In the case of parallel switching of the two springs, both springs act in the opposite direction. Up to the defined pull-out length, the stronger wound spring operates during the pulling out of the separation net from the retracted rest position. After the switch, the stronger wound spring acts against the weaker convenience spring, resulting in a lowering of the return force of the wound spring. As a result, and in the same manner, the reduced suspension forces required for the suspension in the holding devices which are rigidly attached to the vehicle, resulting in a considerably more convenient carrying out of the suspension by the corresponding operator.
The problem of the invention is to provide a separation device of the type mentioned in the introduction, which presents much improved convenience for the operator during the transfer of the flat shaped article into the vertical protective position.
This problem is solved by providing a switch which, by means of a timing element, reduces the winding force of the return spring arrangement in a pull-out position of the flat shaped article or switches it off, and switches it on again after a time period indicated by the timing element. As a result, and in a preferred manner, a short interruption of the pull-out process in any pull-out position or in a pull-out position corresponding to a predetermined length, can result in a switch process to the weak, or completely switched off, return or roll-up force. This can be advantageous, even several times during a pull-out operation, because the timing element is always switched back to the functional position. The switch, as well as the timing element, are advantageously mechanically implemented, but they can also be implemented by electrical, pneumatic or hydraulic means. The switching from the stronger pull-in force to the force-free or low-force pull-out state advantageously occurs in a path-independent manner, whereas the switch back from the force-free or low-force state to the strong winding function is time-dependent.
In an embodiment of the invention, the return spring arrangement is formed by a series-connected or parallel-connected switch of a stronger wound spring and a weaker convenience spring, resulting in a design of the switch which is such that between the rolled-up rest position and the pull-out position, a stronger winding strength becomes active, and starting with the pull-out position, a weaker winding force becomes active for a limited time, during which process the switch of the timing element is assigned in such a manner that the effectiveness of the lower winding force over a defined time period is limited, and, after the expiration of the time period, a switch over to the stronger winding force occurs.
The principle of the spring switch function, as well as the fundamental advantages, correspond to the solution already disclosed in DE 199 27 384.7. In the case of series-connection, the stronger wound spring and the weaker convenience spring act in the same direction. In the case of a parallel switch, the wound spring and the convenience spring act in opposite directions, so that the return force of the wound spring is decreased by the convenience spring. In contrast, in the series connection, the wound spring is switched off, in a simple manner in the first pull-out position, and only the weaker convenience spring is still active. In contrast to the solution described therein, the solution according to the invention does not provide path-dependent, rather it provides for time-dependent, switch from the weaker to the stronger winding force. As a result of the timing element, the smaller winding force is maintained over a defined time period, which depends on the design of the timing element and the incorporation of the timing element in the switch. Thus, the operator has more time available to suspend the flexible flat shaped article, in particular, the separation net, from the first pull-out position into holding devices which are rigidly attached to the vehicle, without the application of the increased return force in the meantime. In addition, after the suspension in the protective position, and after the elapse of the time period, an automatic switch to the stronger winding force occurs, so that, during the renewed operation of pulling into the rest position, the stronger winding force immediately becomes active.
In an additional embodiment of the invention, the wound spring and the convenience spring are achieved by means of a switch installation, which presents a switch element, which acts in cooperation with a time element by means of toothing. The toothing forms a drive, whose translation ratio is appropriate for defining the desired time period which should be available for a convenient operation of suspending, with reduced return force.
In an additional embodiment of the invention, the timing element is designed as a rotating element provided with a pinion, which is positioned off-center with respect to the rotating axis of the winding shaft, and rigidly attached to the housing. The timing element is designed, in particular, as a viscosity brake.
In an additional embodiment, the switch element is in a position which is coaxial with respect to the winding shaft, and it is provided over at least a partial section of its circumference with circumferential toothing. The number of teeth of the pinion, on the one hand, and the radius as well as the number of teeth of the circumferential toothing, on the other hand, define the transformation ratio between the switch element and the viscosity brake, that is the timing element, so that the time span, which is available for the effectiveness of the lower winding force, can be adjusted accordingly.
Additional advantages and characteristics of the invention can be obtained from the claims as well as the following description of preferred embodiment examples of the invention, which are represented with reference to the drawings.